Visitors to the Hawaiian Islands are often welcomed with a friendly "aloha," a flower lei, and a smile. But if you take a hike in the wet forests covering the volcanoes of many of the islands, you may also find another kind of smile  that of the Hawaiian happy-face spider.

By studying the variety of happy-face spiders that live on the different Hawaiian Islands, researchers discovered intriguing patterns that may help us to better understand how variety evolves.